Magnetic leveling unit for elevators



July 15, 1958 .w. BECK MAGNETIC LEVELING UNIT FOR ELEVATORS 4 Sheets-Sheet 1 Filed Oct. 20, 1953 IHII July 15, 1958 w. BECK 2,843,697

MAGNETIC LEVELING UNIT FOR ELEVATORS Filed Oct. 20, 1953 i v 4 Sheets-Sheet 2 MW N m n W" July 15, 1958 w. BECK MAGNETIC LEVELING UNIT FOR ELEVATORS 4 Sheets-Sheet 3 Filed Oct. 20, 1953 July 15, 1958 Filed 001;. 20, 1953 I w. BECK 2,843,697

MAGNETIC LEVELING UNIT FOR ELEVATORS 4 Sheets-Sheet 4 MAGNETIC LEVELING UNIT FOR ELEVATORS Walter Beck, Rock Island, Ill., assignor, by mesue assignments, to Montgomery Elevator Company, a corporation of Delaware Application October 20, 1953, Serial No. 387,103

10 Claims. (Cl. 20087) This invention relates to magnetic leveling controls for elevators, and in particular it relates to the construction of the magnetic switch actuating element used in mag netic leveling controls for elevators.

Automatic and semi-automatic elevators require a control by which they are stopped at floor level under various load and speed conditions, or a similar control may be used to reduce elevator speed close to floor level, or to open the door in the last few inches of elevator travel. Any such operation requires a unit which is automatically actuated as the car approaches a floor level from either direction to operate the switches which perform the desired operation. ,Thus, a leveling control uses two actuating units to control switches for forward and reverse operation of the elevator drive to align the car with the floor. Various actuating devices have been used; but probably the simplest uses magnetic means for moving a switch as the elevator reaches the level at which its further operation is to be controlled.

One difficulty with such magnetic units is that they are difficult to stabilize without using springs of some sort to retain the magnetic control element in a desired position. Springs are unsatisfactory because of fatiguing and breakage, which may result in malfunctioning of the leveling control. If the magnet is stabilized merely by overbalancing one end, it may be jarred out of position if there is any unusual jolt or jar to the elevator car during loading.

In accordance with the present invention I have provided a stable magnetic actuating element for an electric switch by positioning a fixed magnet and a movable magnet in spaced relationship with their like poles adjacent each other so that their natural magnetic repulsion tends to stabilize the movable magnet of the pair. Thus, the movable magnet is held firmly in a fixed position, and may be moved so as to close the switch by the simple expedient of moving an iron neutralizing vane, or plate, into the space between the two magnets. This effectively insulates the two magnets from one another, and the flux path for the magnetic force from the movable triagnet passes through the iron vane so that the movable magnet is drawn toward the vane and its movement actuates the electric switch.

The invention is illustrated in the preferred embodiment in the accompanying drawings in which:

Fig. l is a perspective view of an elevator car and a portion of the shaft with the device of the present invention mounted thereon;

Fig. 2 is a central vertical sectional view of the magnetic actuating device in its stabilized condition with the end of a vane approaching the magnetic field from. above;

Fig. 3 is a side elevational view of the magnetic actuating element with a portion of the casing broken away to show the movable magnet in its other position, with the vane interposed between the twomagnets;

Fig. 4- is a front elevational view of the magnetic switch actuating unit;

rates Patent l 2,843,697 Patented July 15, 1958 Fig. 5 is a section taken as indicated along the line 5-5 of Fig. 6;

Fig. 6 is a section taken as indicated along the line 6-'6 of Fig. 4;

Fig. 7 is a fragmentary top plan view of the elevator car and shaft with the device in place thereon;

Fig. 8 is a fragmentary side elevational view similar to Fig. 7; and

Figs. 9, l0 and 11 are diagrammatic views of the magnetic switch and circuit arrangement in three different positions of the elevator car with respect to the iron neutralizing vane.

Referring to the drawings in greater detail, and referring first to Fig. 1, an elevator car, indicated generally at 20, includes the usual stile 21, lifting beams 22, platform 23, side walls 24 and top 25. The platform is stabilized in the stile by means of slant rods 26. An upright angle member 27 is secured to the lifting means 22 and to the lower portion of the car 20 to serve as a bracket for a pair of identical magnetic switch actuating assemblies which are vertically spaced along the angle member 27, the upper one being designated as 28a and the lower as 28b. As seen in Fig. 7, the elevator car 20 runs in an elevator shaft 29 which has on one wall a continuous vertical support 30 for a guide rail 31, and mounted on the support 30 at appropriate intervals adjacent the various floor levels are brackets 32 for iron plates 33 having inwardly extending neutralizing vane portions 33a which cooperate with the magnetic switch elements 28 as will be described.

The magnetic switch units being identical, only the upper unit 28a will be described in detail. Referring now to Figs. 26 the magnetic switch unit 28a includes a casing 35 providing a frame which is formed of nonmagnetic material such as molded plastic, aluminum or other non-magnetic metal. On the front of the casing 35 is a non-magnetic closure plate 36 which has its end portion inclined rearwardly as seen at 37 so that if the neutralizing vane 33a and unit 28a are out of alignment the vane will be deflected to the front of the casing. As best seen in Fig. 6, on one wall of the casing 35 is secured a bracket 38 which has a transverse supporting portion 39 spaced from and parallel to the front closure 36 of the casing. A bar magnet 40 is secured to the inner face of the bracket arm 39 by means of a pair of screws 41 and a clamping plate 42 of non-magnetic material which has outwardly inclined upper and lower margins 43 to deflect the vane 33a into the space between the bracket 38 and the casing 35 if necessary. The bar magnet 40 is preferably formed of a highly magnetic alloy such as Alnico. It is mounted upon the bracket 39 with its north pole, for example, at the right as shown in 6.

Referring particularly now to Figs. 2, 3 and 5, a pivot pin 44 extends transversely of the casing 35 slightly above the plane of the bracket 38, and serves as a support for a rock member 45 which may rock about said pivot 44 and which has at its lower end a bracket 46 which is secured by a screw 47 the rear end of which acts as an abutment stop for the rock member 45. A horeshoe magnet 48 is mounted on the bracket 46 with its poles adjacent the corresponding poles of the bar magnet 40, as seen. in Fig. 6, so that the bar magnet 40 and horseshoe magnet 48 repel each other and stabilize the rock member 45 in'the position of Fig. 2. A set screw 49 extends through the back of the casing- 35 in alignment withthe abutment screw 47 so as to adjustably limit the move-' ment of the rock member 45. A second set screw 50 is aligned with the upper end of the rockmember 45 so as to adjustably limit the rocking movement of the rockmember in the opposite direction. As best seen in Fig.

3 5 two copper contact strips 51 are fastened to the face of the rock member 45 by a screw 52 and project upwardly into the upper end portion of the casing 35.

Secured to the top of the casing 35 is a dielectric base member 53 for a pair of fixed contacts 54 which cooperate with the contact strips 51 to form electric switches. Each of the fixed contacts 54 is held in place by suitable screws, one of which provides a binding post 55 for a wire 56, the two wires 56 from the two fixed contacts 54 passing out of the rear of the casing 35 through a conduit pipe 57.

As best seen in Fig. 7, the neutralizing vane 33a of the iron plate 33 extends into a plane between the front closure 36 for the casing 35 and the bar magnet 40.

Referring now particularly to Figs. 2 and 3, when the neutralizing vane 33a of the plate 33 is clear of the space between the horseshoe magnets 48 and the bar magnets 40, as seen in Fig. 2, the magnetic repulsive force of the two magnets retains the rock member 45 with the contact arms 51 spaced away from the fixed contacts 54. However, when the neutralizing vane 33a is interposed between the two magnets as seen in Fig. 3 the bar magnet 40 and the horseshoe magnet 48 are mag netically insulated from one another and the magnetic lines of force of the horseshoe magnet 48 pass through the neutralizing vane 33a, drawing the horseshoe magnet toward the vane and tilting the rock member 45 rearwardly against the stop 50 at the upper end of the casing so as to close the electric circuit through the contacts 51 and 54. As best seen in Fig. 8, and diagrammatically in Figs. 9-11, the neutralizing vane 33 is not quite as long as the space between the magnets in the two vertically spaced switch units 28a and 28b, so that both of the switches can not be simultaneously actuated. Thus, in the position shown in Fig. 11, both of the switches in the magnetic switch control unit 28 are open and the motor M is not operating. If the elevator car 20 moves down to the position of Fig. 10, the magnets of the upper member 28a will be insulated from one another by the upper end of the neutralizing vane 33 so as to close the upper switches, which actuate the motor M to raise the elevator a sufiicient distance to again open the upper switches. If, on the other hand, the elevator rises too far and assumes the position of Fig. 9, the lower switch unit 28b will have its magnets insulated by the lower end of the neutralizing vane 33a, closing the switches in that unit and operating the motor M in the opposite direction to lower the position of the car until it again is in the neutral position shown in Figs. 8 and 11.

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations are to be understood therefrom, as some modifications will be obvious to those skilled in the art.

I claim:

1. In a magnetic switch: a frame of non-magnetic material; spaced first and second supports on said frame; a fixed magnet on said first support with one pole adjacent said second support; a rigid carrying member movably mounted on said second support; a second magnet on said carrying member with its pole like said one pole adjacent said first support and opposed to said one pole, so that the mutual repulsion of said like poles holds the carrying member in a stable position; a fixed switch contact supported by the frame; a movable switch contact supported by the frame in operative relationship to the fixed contact, said movable contact occupying a normal first position relative to the fixed contact and being movable to a second position by shifting of the carrying member from said stable position; and a neutralizing member including magnetizable material which may be interposed between said like poles to neutralize said repulsion and attract the second magnet to shift the carrying member from its stable position.

2. In a magnetic switch: a frame of non-magnetic material; spaced first and second supports on said frame; a fixed magnet on said first support with one pole adjacent said second support; a rigid carrying member movably mounted on said second support; a second magnet on said carrying member with its pole like said one pole adjacent said first support and opposed to said one pole so that the mutual repulsion of said like poles holds the carrying member in a stable position; a fixed switch contact supported by the frame; a switch contact on said carrying member in operative relationship to and occupying a normal first position relative to the fixed contact, said contact being movable to a second position by shifting of the carrying member from said stable position; and a neutralizing member including magnetizable material which may be interposed between said like poles to neutralize said repulsion and attract the second magnet to shift the carrying member from its stable position.

3. In a magnetic switch; a frame of non-magnetic material; spaced first and second supports on said frame; a fixed magnet on said first support with its poles in a common plane adjacent said second support; a rigid carrying member movably mounted on said second support; a second magnet on said carrying member with its poles in a plane adjacent and parallel to said common plane, the like poles of said magnets being opposed so that the magnetic repulsion holds the carrying member in a stable position; a fixed switch contact supported by the frame; a movable switch contact supported by the frame in operative relationship to the fixed contact, said movable contact occupying a normal first position relative to the fixed contact and being movable to a second position by shifting of the carrying member from said stable position; and a neutralizing member including magnetizable material which may be interposed between said like poles to neutralize said repulsion and attract the second magnet to shift the carrying member from its stable position.

4. In a magnettic switch: a frame of non-magnetic material; spaced first and second supports on said frame, a fixed bar magnet on said first support with its poles in a common plane adjacent said second support; a rigid carrying member movably mounted on said second support; a horseshoe magnet on said carrying member with its poles in a plane adjacent and parallel to said common plane, the like poles of said magnets being opposed so that the magnetic repulsion holds the carrying member in a stable position; a fixed switch contact supported by the frame; a movable switch contact supported by the frame in operative relationship to the fixed contact, said movable contact occupying a normal first position relative to the fixed contact and being movable to a second position by shifting of the carrying member from said stable position; and a neutralizing member including magnetizable material which may be interposed between said like poles to neutralize said repulsion and attract the second magnet to shift the carrying member from its stable position.

5. In a magnetic switch: a frame of non-magnetic material; a first support on said frame; a fixed magnet on said first support; a support pivot on the frame adjacent one pole of the fixed magnet; a rigid rock member on said support pivot; a second magnet on said rock member with a pole adjacent the like pole of the fixed magnet so that their mutual repulsion holds said rock member in a stable position; a, fixed switch contact supported by the frame; a movable switch contact supported by the frame, said movable contact occupying a normal first position relative to the fixed contact and being movable to a second position by shifting of the rock member from said stable position; and a neutralizing member including magnetizable material which may be interposed between said like poles to neutralize said repulsion and attract said second magnet to shift the rock member from its stable position.

6. In a magnetic switch: a frame of non-magnetic material; a fixed magnet on said first support; a support pivot on the frame adjacent one pole of the fixed magnet; a rigid rock member on said support pivot; a second magnet on said rock member with a pole adjacent the like pole of the fixed magnet so that their mutual repulsion holds said rock member in a stable position; a pair of set screws extending through the frame with their ends adjacent the rock member so as to adjustably limit the swing of the rock member in both directions; a fixed switch contact supported on the frame; a switch contact on the rock member in operative relationship to and occupying a normal first position relative to the fixed contact, said contact being movable to a second position by shifting of the rock member from said stable position; and a neutralizing member including magnetizable material which may be interposed between said like poles to neutralize said repulsion and attract said second magnet to shift the rock member from its stable position.

7. In a magnetic switch: a frame of non-magnetic material; a fixed magnet supported on said frame with its two poles in a given plane; a pivot on the frame in a plane parallel to said given plane; a rigid rock memher on said pivot; a second magnet on said rock member with its poles in a plane parallel to said given plane and adjacent the like poles of the fixed magnet so that their mutual repulsion holds said rock member in a stable position; a fixed switch contact supported by the frame; a movable switch contact supported by the frame in operative relationship to the fixed contact, said movable contact occupying a normal first position relative to the fixed contact and being movable to a second position by shifting of the rock member from said stable position; and a neutralizing member including magnetizable material which may be interposed between said magnets to neutralize said repulsion and attract the second magnet to shift the rock member from its stable position.

8. In a magnetic switch: a casing of non-magnetic material; a bracket on the outside of said casing with a horizontal leg parallel to and extending transversely of a wall of the casing; a bar magnet mounted flat on said leg of the bracket; a pivot in the casing which is parallel to said leg; a rock member on said pivot which has a portion opposite said bar magnet; a horseshoe magnet supported on said portion of said rock member with its poles adjacent and equidistant from like poles of the bar magnet so that their mutual repulsion holds the rock member in a stable position; a fixed switch contact supported by the frame; a movable switch contact supported by the frame in operative relationship to the fixed contact, said movable contact occupying a normal first position relative to the fixed contact and being movable to a second position by shifting of the rock member from said stable position; and an iron plate parallel to said wall of the casing so that relative vertical movement of the casing and plate may move the plate between the magnets to neutralize said repulsion and attract said horseshoe magnet to shift the rock member from its stable position.

9. The device of claim 8 in which the casing includes an upright front cover of non-magnetic material between said magnets which has its upper and lower ends inclined rearwardly to serve as deflector plates for the iron plate.

10. The device of claim 9 in which the bar magnet is secured to the bracket by means of a clamping plate which has inclined upper and lower surfaces adapted to deflect the iron plate into the space between the magnets.

References Cited in the file of this patent UNITED STATES PATENTS 1,287,896 Crane Dec. 17, 1918 1,844,514 Mattingly Feb. 9, 1932 2,044,152 Clancy June 16, 1936 2,178,839 Landon Nov. 7, 1939 2,189,597 Wells Feb. 6, 1940 2,235,104 Greenly Mar. 18, 1941 2,285,244 Williams June 2, 1942 2,482,529 Williams Sept. 20, 1949 2,521,568 Crane Sept. 5, 1950 2,522,815 Early Sept. 19, 1950 98,214 Borden May 27, 1952 2,666,110 Berkovitz Ian. 12, 1954 FOREIGN PATENTS 440,907 Great Britain Jan. 8, 1936 

